ABSTRACT
This research was conducted to evaluate the methylene blue dye adsorption by piaçava fibers. The effects of adsorbent amount, pH, kinetics, equilibrium, and thermodynamics were analyzed, as well as the adsorbent performance in the treatment of synthetic textile effluents. The adsorbent characterization was also performed. Experimental kinetic data were fitted with pseudo-first-order, pseudo-second-order, and Elovich models. The equilibrium tests were done at 298, 308, and 318 K, and the models of Freundlich, Langmuir, Redlich-Peterson, and Sips were used. The adsorption was favored using 0.025 g of adsorbent, pH 10, and 318 K. The Elovich model provided better fit to kinetic data. The equilibrium experimental points were well represented by the Sips model. The maximum experimental adsorption capacity of methylene blue dye was 427.3 mg g-1. It was verified a spontaneous, favorable, and endothermic adsorption. Piaçava fiber was a promising low-cost material to be used for color removal in effluents containing methylene blue.
Subject(s)
Coloring Agents/chemistry , Methylene Blue/chemistry , Adsorption , Kinetics , Textiles , ThermodynamicsABSTRACT
Pará chestnut husk (Bertholletia excelsa) (PCH), an agro-industrial waste largely generated in Brazil, was employed as a low-cost and efficient biosorbent to remove the cationic dyes Crystal Violet (CV) and Methylene Blue (MB) from aqueous media. PCH presented an amorphous structure containing carboxylic acids, esters, ketones and aldehydes on the surface. Non-porous and irregular particles were also observed. For both dyes, the biosorption capacity was favored under acid conditions. Equilibrium was attained within 40 min at 25 °C with a PCH dosage of 0.5 g L-1. The biosorption kinetic curves were satisfactory explained by the pseudo-first-order model. The Freundlich model was best for representing the equilibrium curves. The maximum biosorption capacities were 83.6 and 83.8 mg g-1 for CV and MB, respectively. PCH was efficient for treating a simulated textile effluent containing several dyes and chemicals, achieving a color removal of 90%. In this way, PCH can be considered as an option for treating colored effluents containing textile dyes.
Subject(s)
Bertholletia/chemistry , Coloring Agents/chemistry , Industrial Waste/analysis , Adsorption , Brazil , Cations , Gentian Violet , Hydrogen-Ion Concentration , Kinetics , Methylene Blue , Textile Industry , Waste Disposal, Fluid , Water , Water Pollutants, Chemical/chemistryABSTRACT
A colangite é uma afecção do trato biliar com significativa morbi-mortalidade associada. Muitos pacientes com colangite aguda respondem à antibioticoterapia. Entretanto, aqueles com a forma severa ou tóxica da doença usualmente não respondem, necessitando de drenagem biliar de emergência
Subject(s)
Humans , Male , Female , Middle Aged , Cholangitis/complications , Cholangitis/diagnosis , Cholangitis/physiopathology , Cholangitis/pathology , Acute Disease/mortality , Bile Duct Diseases/physiopathology , Bile Duct Diseases/mortality , Bile Duct Diseases/pathologyABSTRACT
Os autores se propõem a realizar atualização e análise crítica das colostomias, enfatizando noções sobre conceito, indicações, classificação, cuidados pré-operatórios, complicações e fechamento das mesmas
Subject(s)
Humans , Male , Female , Colostomy/classification , Colostomy/methods , Colostomy , Gastrointestinal Transit , Surgical StomasABSTRACT
Artrite reumatóide é uma poliartrite progressiva crônica, com achados sistêmicos variados, associada com substancial inaptidão e perdas econômicas. O tratamento bem sucedido visa limitar o dano à articulação e a perda funcional. Portanto, exige diagnóstico precoce e início oportuno de agentes modificadores da doença
